Method for cutting sheet material



ug. 16, 1966 lt 5.5551 3,266,350

METHOD FOR CUTTING SHEET MATERIAL Original Filed June 25, 1961 INVENTOR. doh/7 6. 565% United States Patent O 3 266,350 METHOD FOR CU'IzTING SHEET MATERIAL John S. Best, Midland, Mich., assignor to The Dow Chemical Company, Midland, Mich., a corporation of Dela- This application is a division of application Serial No. 119,157, tiled June T23, 1961, now Patent No. 3,174,368.

This invention relates to an improved method of cutting embossed sheet material. l

It more particularly relates to an improved method of cutting sheet material in roll form.

Plastic and metal sheets frequently are embossed with attractive and utilitarian designs. Generally, such embossed sheet material is initially prepared and stored in the form of a relatively large supply roll. Frequently, for ymany applications, narrower widths are desirable in preference to the full width of the supply roll which, in many cases, will be 4, 5 or even 6 -or more feet. Advantageously, such supply rolls are slit into narrower widths more suitable to the customers requirements and rewound into narrower rolls. Usually in such an operation, an embossed or other similarly deformed lm or sheet must be unwound, slit and rewound into two or more rolls. In certain cases, supply rolls of solid flat lm, that is, not embossed m-ay be4 slit by rotating the supply roll in a lathe-like device, holding a suitable cutting tool against the rolland unwinding a narrow strip which may be discarded `as scrap or alternately a relatively wide strip may be removed and rewound into a narrower roll leaving the original supply roll in the form of two narrower rolls on a common core. When such a technique is applied to an embossed ilm, cutting is extremely difficult because an embossed -lm generally can not be wound into a tight supply roll, but is relatively loose and will deform readily under the pressure of `a cutting tool. Such deformation gives rise to undesirable friction in the ease of thermoplastic -lms and subsequent fusion of the edges. Usually in the case of foils `and metallic sheets such as aluminum and the like, undesired distortion and deformation will occur adjacent the severed edges.

It is an object of this invention to provide an improved apparatus for the slitting of the supply roll of embossed lm.

It is a further object of this invention to provide an improved method of slitting a supply roll of embossed film.

lt is yet another object of this invention to provide a method and apparatus for the slitting of a supply roll of an embossed foil which will prevent overheating and deformation ofthe slit edges.

These benefits and other advantages may be obtained by employing in the slitting of the roll of embossed sheet material an apparatus comprising: a support member having rotatably mounted thereon means to engage opposite ends of a roll of sheet material, and rotate said roll about its axis of generation, at least one of said means to engage an `end of said roll being pervious to fluid and adapted to be in communication with pressurized iluid supply means `and means for slitting said sheet while wound `on said roll.

The invention also contemplates a method of slitting a supply roll of embossed foil comprising rotatably supporting a supply roll of embossed sheet material, said roll being rotatable about its axis of generation, applying a uid pressure to at least one end face of said roll, said pressure being sufficient to inflate and hold the outer layer -of said roll under tension, rotating said roll, slitting 3,266,350 Patented August 16, 1966 Pice at least one layer per revolution of the roll of said embossed sheet and removing at least one slit portion from the supply roll as a strip.

Further features and .advantages of the invention will be more apparent in the following description and specification taken in connection with the accompanying drawing wherein:

In FIGURE 1 there is illustrated -a schematic, partlyin-section view of a method and apparatus of the invention.

FIGURE 2 is a face View of the roll and engaging means in accordance with the invention.

FIGURE 3 is a cross sectional view of a plurality of layers of an embossed sheet which may be slit in accordance with the invention. l In FIGURE 1 there is illustrated `a schematic partlyin-section view of an apparatus in accordance with the invention generally designated by the reference numeral 10. The apparatus 10 comprises-a pair of roll engaging assemblies 11 and 12. The roll engaging assembly 11 is rotatably mounted to the journal bearing or supporting means 14. The assembly 12 is mounted in the bearing ,or support means 16. Resilient means 17 and 18 are provided between the journal bearings 14 and 16 and the end assemblies 11 and 12 to resiliently urge the end assemblies toward each other and perform the function of thrust bearings. The end assembly 11 comprises a housing 20 deiining a .plenum chamber 21 having supported therein a permeable disc 22. The housing 20 denes a fluid inlet port 24 in operative association with a swivel joint 25. The swivel joint 25 in turn is in communication with a iluid supply means 27. The end assembly 12 is constructed in a similar manner to an end assembly 11. A supply roll 29 of embossed sheet or film 30 having ends 31 and 32 is mounted between the end assemblies 11 and 12. The ends 31 Iand 32 are in engagement with the permeable plates 22. The supply roll 29 has a core or mandrel 33 which is inserted into a recess 29 in the plate 22. In operative engagement with the surface of the roll 29 are two knives 35 and 36 which sever the strip 37 from the main body of the supply roll 30.

In FIGURE 2 there is illustrated an end view of the end assembly 11 showing the relationship between the housing 20, the permeable plate 22, the recess 28 and the iluid port 24.

FIGURE 3 is a cross sectional view of a plurality of superimposed l-ayers of embossed film 38, showing spaces 40 between layers of the tilm.

Advantageously, in operation of the invention the loose end of the lm 30 of a supply roll 29 is secured to the main body of the roll by means of adhesive tape or similar fastening means. The roll 29 is then positioned between lche end assemblies 11 and 12, the projecting core 3'3 of the roll 30 being inserted into the aperture 28 of -the porous plates 22 of an assembly 11 and being similarly engaged by the end assem'bly 12 on the opposite end.

The springs 17 and 19 serve to maintain a tight engagement between the faces 22 and the roll ends 31 and 32. Fluid under pressure such as compressed air which is fed from a supply source through a rota-ry joint 25 and int-o the plenum chamber 21. The a-ir or fluid then passes through the permeable plates 22 and serves to inflate the loosely wound roll 29, causing the outer layers thereof to distend outwardly. The roll end engaging means are rot-ated and the cutting knives 35 and 36 are simultaneously brought intro engagement with the outer layer of {il-m 30 o'f the roll 29. After an initial cut is made about the circumference of the roll 29, thestrip 37 is loosened and removed. The supply roll 29 is subsequently rotated. The cutting knives 35 and 36 are advanced into the roll at a rate of at least one thickness of the embossed foil per revolution of the supply roll. Thus, this operation may be continued until the supply roll 29 is severed into 3 parts, two rolls corresponding to the end portion-s 31 and 32 and a third portion corresponding to the removed strip 37.

Slitting a supply roll of embossed lm in accordance with the invention may be carried out at relatively high speeds, that is, from 500 to 2,000 feet per minute on conventional equipment. Such speed appears to be limited by the geometry of the supply roll and dynamic balance of the assembly as a Whole.

The pervious plate 22 may be fabricated from a Wide variety of material. In certain cases a metal plate may be employed having a plurality of holes drilled therethrough in communication with the plenum chamber 21. Generally it is advantageous in most operations to provide a graded air distribution across the face of such a plate and larger openings are disposed toward a central portion of the plate and smaller toward the periphery. Beneficially, sintered metal plates are employed or face plates are prepared from a thin perforated smooth sheet of metal and backed with a relatively heavy metal grill or lattice. yIn cases Where roll end regularity, that is, the end faces of the roll do not have even and uniform geometry a very satisfactory face plate 22 may be prepared from a heavily perforated metal plate having an open celled sponge or foam plastic material adhered thereto to enga-ge and seal the irregular ends.

By Way of further illustration, embossed rolls of polyethylene film were cut in accordance with the invention and no tendency was observed of deformation or fusion of the edges together at speeds as high as about 1,000 feet per minute.

As is apparent from the foregoing specication, the apparatus and method of the present invention are susceptible of being embodied with various alterations and modifications which may differ particularly from those that have been described in the preceding specification `and description. For this reason, it is to be fully understood that afll of the foregoing is intended to be merely illustrative and is not to be construed or interpreted as being restrictive or otherwise limiting of the present invention, excepting a-s it is set forth and derined in the hereto appended claims.

What is claimed is:

1. A method of slitting a supply roll of embossed foil comprising rotatably supporting a supply roll of embossed sheet, said roll being rotatable about its axis of generaltion, applying a iiuid pressure to at least one end face of said roll, said pressure being suflicient to inflate and hold lthe outer layer off said roll under tension, rotating said roll, slitting at least one layer per revolution of the roll of said embossed sheet and removing at least one slit vportion from the supply roll as a strip.

2. In a method lor slitting a supply roll of embossed foil comprising rotatably supporting said supply roll and rotating said roll about its axis of generation, rotating at least one layer per revolution of the roll of said embossed sheet, and removing at least one slit portion from the supply roll as a strip the improvement which comprises providing a fluid pressure to the end faces of said roll, said pressure being suicient to inate and hold the outer 'layer of said roll under a tension sufficient to maintain the layer of embossed sheet -being in engagement with the slitting means.

3. The method of claim 2, wherein said fluid pressure is provided by air at a pressure greater than atmospheric.

4. The method of claim 3, wherein said air pressure is applied to both ends of said supply roll.

No references cited.

WILLIAM W. DYE-R, JR., Primary Examiner. HARRISON L. HINSON, Examiner. 

1. A METHOD OF SLITTING A SUPPLY ROLL OF EMBOSSED FOIL COMPRISING ROTATABLY SUPPORTING A SUPPLY ROLL OF EMBOSSED SHEET, SAID ROLL BEING ROTATABLE ABOUT ITS AXIS OF GENERATION, APPLYING A FLUID PRESSURE TO AT LEAST ONE END FACE OF SAID ROLL, SAID PRESSURE BEING SUFFICIENT TO INFLATE AND HOLD THE OUTER LAYER OF SAID ROLL UNDER TENSION, ROTATING SAID ROLL, SLITTING AT LEAST ONE LAYER PER REVOLUTION OF THE ROLL OF SAID EMBOSSED SHEET AND REMOVING AT LEAST ONE SLIT PORTION FROM THE SUPPLY ROLL AS A STRIP. 